1. Field of the Invention
This invention relates to a range finding optical mechanism having a range finding optical axis regulating mechanism.
2. Description of the Prior Art
Devices of the type in which object images are formed on photoelectric converter means arranged in the form of a row (such as, for example, a photosensor array) by a pair of imaging optical systems disposed with a base line length interposed therebetween and the spacing between the two images is electrically detected to thereby know the distance to the object, have a disadvantage that unless the two images are formed on the row-like photoelectric converter means in the same focused condition and at correct relative positions, a correct range finding signal cannot be obtained and an incorrect distance detection is effected.
Particularly, because the photoelectric converter means is arranged in the form of a row, accurate photoelectric conversion cannot be accomplished unless the object images produced by the pair of imaging optical systems are projected equally on this row.
Also, where the range finding optical system is provided separately with respect to the phototaking optical system, the optical axis of the range finding optical system differs from the optical axis of the phototaking optical system and therefore, the range of range finding (hereinafter referred to as the range finding view field) moves in accordance with the object distance. Also, where the phototaking lens system is a zoom lens system having a magnification changing effect, the size of the range finding view field seen through the viewfinder apparently varies.
On the other hand, in a distance detecting method wherein the photosensor array is laterally placed, the longitudinal size of the sensor is smaller than the lateral size of the sensor and therefore, it is necessary to indicate the range of the range finding view field within the viewfinder and the system should be designed such that the range finding view field varies within that range. However, if a range finding block supporting the entire range finding optical system and the phototaking optical system are simply assembled together, it will be difficult due to the accuracy of parts to have the range finding view field correctly contained within said range.
Accordingly, there has heretofore been a method of regulating the range finding block by means of a three-point screw or the like to set the range finding view field at a predetermined location within the viewfinder, but in this method, it has not been possible to separate horizontal and vertical regulations from each other and fine regulation has been very difficult.